The present invention relates to multi-channel, bi-directional fiber optics data link "(FODL") systems, and more particularly to an improved switch for such systems.
Conventional optical fiber switches rely on electro-mechanical switches to physically align different input and output fiber pairs for signal transmission. The small fiber core size makes precision alignment of these fiber pairs a challenge. The use of moving parts in the conventional fiber switch also raises reliability concerns especially under severe operation conditions, such as missile launch. Furthermore, a missile launcher (or surveillance system) with more than two missiles (or outposts) requires several 1.times.2 switches in cascade to cover all possible channel connections. This results in a complicated switch control and longer switch time.
Although an integrated optics, channel waveguide, electro-optic (EO) switch requires no moveable parts, its performance is sensitive to the optical wavelength and the insertion loss of fiber-to-channel-waveguide coupling. It is also difficult to provide switching for a bi-directional FODL system that uses two optical wavelengths for two-way transmission.
Another optical switch design uses acoustic-optics (AO) beam deflection to steer the connecting fiber channels This scheme again is sensitive to the signal optical wavelength and suffers high loss due to poor fiber-AO device-fiber coupling. "Modulation and switching of light in dielectric waveguides," J. M Hammer, p. 139, "Integrated Optics" edited by T. Tamir, Springer-Verlag, Berlin and New York, 1975.
It would therefore be advantageous to provide a multi-channel, bi-directional fiber optic data link system which does not require the-use of electro-mechanical, electro-optic or acoustic-optics switches for switching light signals.